Video: Pure magic

Move over, Hedwig. In "Harry Potter and the Prisoner of Azkaban," Harry trades in his trusty white owl for a bird of a bigger feather. It’s not just any hippogriff. Author J.K. Rowling created the lovable and sometimes unpredictable beast named Buckbeak.

It took the animators at London's Framestore CFC more than a year of cutting-edge computer wizardry to bring Buckbeak to the big screen. The result uses never before seen special effects to create one of the most magnificent and realistic creatures in film history.

But what exactly is the mythical creature known as a hippogriff?

"He's basically a combination of a horse and a bird," says visual effects supervisor Tim Burke. "His front half is a bird, and his back half is a horse."

Half horse and half bird equals one big challenge for the animators. To start, the team took a field trip.

"We spent a lot of time down at the zoo," says CG supervisor David Lomax, "going to bird sanctuaries to study their movement and what they looked like, as well as taking many pictures of horses and studying horses in fields."

After building 3-D models to plan the physics of how a bird and horse can move as one beast, the team then sunk their talons into one of the most daunting challenges in the animation world today -- feathers.

"Doing believable feathers has been one of the holy grails," says Lomax. "There's been plenty of attempts to do it, some very good attempts. We like to think our attempt is the best so far.

The animators decided the only way to make Buckbeak look as real as possible was to compromise on nothing. So they created every feather on the hippogriff, every filament on every feather, and every barb on every filament. They then wrote a computer program to get all the different feathers to move together just like the real thing.

Next, to determine Buckbeak's size, the animators worked with the film's creature effects supervisor Nick Dudman, who built a full-scale version of the mythical beast. We got to meet Nick's creation in person and learn a little about the etiquette of greeting a hippogriff, including the fact that one should bow before getting close.

But the animators weren't out of the woods yet. You've heard the phrase, "when pigs fly," but try getting a 7-foot tall hippogriff to fly, even if he is only virtual.

"To fly something the scale of a horse, you need big wings," says visual effects supervisor Roger Guyett. "And if you look at the creature, we've figured out basically the right proportions were about 30 odd feet, 28 feet, for a wingspan of that size."

There was only one problem: Wings that big would drag on the ground and even trip a hippogriff. So the animators did the only sensible thing.

"Essentially we cheated," says Burke. "We had smaller wings when he was on the ground and bigger wings when he was flying. But hopefully you won't notice."

Now the hippogriff with his incredible shrinking wings was ready for his close up. In one scene, Buckbeak takes Harry Potter on a wild ride. First the filmmakers shot the background plates. Next, to simulate Harry riding Buckbeak, actor Daniel Radcliffe took a spin on a motion-control rig -- kind of a high-tech bucking bronco -- shot in front of a blue screen.

The animators then painstakingly married together the different layers of the sequence: their virtual hippogriff, the blue screen with Harry and even animated dust from Buckbeak's hooves. With all the layers seamlessly integrated, audiences should see only one thing -- pure magic.

"That's the biggest compliment," says Carl Mooney. "If people don't know you were involved, then it was a success."

Dateline wires the home of a volunteer, Jenny, from top to bottom with hidden cameras. Then she called repairmen to her house for a simple problem we created as a test with Jenny's pool. NBC's Chris Hansen reports.